• 제어로봇시스템학회논문지
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• 제6권9호
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• pp.803-812
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• 2000

In this paper we introduce a model based centralized hierarchical controller for cooperative team of soccerplaying multiple mobile robots. The hierarchical controller is composed of high-level and low-level controllers. Using the coordinates information of objects from the vision are simple models of multiple mobile tobots on the playground. Subsequently, the high level controller selects and action model corresponding to the perceived state transition model and generates subgoal and goal-velocity, from which the low level controller generates trajectory of each wheel velocity of the robot. This two layered simplicity. The feasubility of the control strategy has been demonstrated in an implementation for real soccer games at a MiroSot league.

• 제어로봇시스템학회논문지
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• 제14권2호
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• pp.105-110
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• 2008

This paper presents a control method to maintain stable mold level for unsteady bulging in high speed casting. The stabilizing mold level is an important factor to get high quality products. But, for various reasons, there are several disturbance factors which make mold level unstable. Bulging is one of disturbance factors and considered for the current stage of study. We design a disturbance observer to attenuate the effect of bulging which is periodic mold level disturbance. Since the period of bulging varies with the casting speed, the parameters of disturbance observer are changed by the casting speed. Simulation is illustrated to demonstrate stable performance of the proposed method in comparison with a previous method in a variable operating frequency.

• Nuclear Engineering and Technology
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• 제44권8호
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• pp.911-918
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• 2012

Steam generator level control at low power is difficult due to its adverse thermal hydraulic properties, and is usually conducted by an operator. The basic model predictive control (MPC) is similar to the action of an operator in that the operator knows the desired reference trajectory for a finite period of time and takes the necessary control actions needed to ensure the desired trajectory. An MPC is based on a model; the performance as well as the efficiency of the MPC depends heavily on the exactness of the model. In this study, steam generator models that can describe in detail its thermal hydraulic behaviors, particularly at low power, are used in the MPC design. The design scope is divided into two parts. First, the MPC feedwater controller of the feedwater station is determined, and then the MPC level controller for the overall system is designed. Because the dynamic properties of a steam generator change with the power levels, a realistic situation is simulated by changing the transfer functions of the steam generator at every time step. The resulting MPC controller shows good performance.

• Journal of Power Electronics
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• 제11권4호
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• pp.583-590
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• 2011

Three-level NPC inverters have been put into practical use for years especially in high voltage high power grids. This paper researches three-level active power filters (APFs). In this paper a mathematical model in the d-q coordinates is presented for 3-phase 3-wire NPC APFs. The deadbeat control scheme is obtained by using state equations. Canceling the delay of one sampling period and providing the predictive value of the harmonic current is a key problem of the deadbeat control. Based on this deadbeat control, the predictive output current value is obtained by the state observer. The delay of one sampling period is remedied in this digital control system by the state observer. The predictive harmonic command current value is obtained by the repetitive predictor synchronously. The repetitive predictor can achieve a better prediction of the harmonic current with the same sampling frequency, thus improving the overall performance of the system. The experiment results indicate that the steady-state accuracy and the dynamic response are both satisfying when the proposed control scheme is implemented.

• 한국식생활문화학회지
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• 제18권4호
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• pp.396-405
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• 2003

The purpose of this study was to investigate the changes of obesity and depression level of obese children on body weight control program. The body weight control program included nutrition education, psychotherapy and exercise for weekly session during 9 months. The results from this study were as follows. A total of 27 obese children participated in this study. The average age of children was 11.7 years, 70% of children had regular exercise. Average exercise time was 1.2 hours and watching television time was 1.8 hours. Children's serum composition were within normal ranges. Rohrer index(RI) was significantly decreased to 163 from 167(p<0.001) and BMI was significantly decreased to 23.9 from 24.5(p<0.01) after body weight control program. There was not significant difference in depression score after body weight control program and there was not significant correlation between obesity and depression level. The response tendency of depression items indicated obese children had negative depression feelings and couldn't have hopeful mind to the future. But there were significant increase(p<0.05) in depression and hopeful mind in factor analysis. The suggestion and limitations of this study were discussed. These results suggest that body weight control program including nutrition education, exercise and psychotherapy may be effective for helping obese children.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 제13회 신호처리 합동 학술대회 논문집
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• pp.533-536
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• 2000

We consider the design of quadrature amplitude modulation (QAM) transceivers f3r fixed wireless communications. The use of adaptive power control in the transmitter (Tx) can provide BER performance robust to fading and improved BER performance. The BER performance is evaluated by analytical and simulation results when multi-level QAM transceiver employing power control in the Tx is applied to fixed wireless channel with flat fading and frequency selective fading. The effect of power control parameters such as power control range and power control step size is investigated

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.1229-1232
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• 1996

This paper proposes the passive redundancy algorithm of multi-controller structure applicable to the steam generator level control system in the low power operating range. In the passive redundancy scheme of multi-controller structure, two suitable controllers exist if the plant is strongly stabilizable. One of the two controllers can be selected arbitrarily only if it is stable. In particular, this paper shows that the passive redundancy scheme can be efficiently used with PID and GPC control algorithms through simulation studies on the control of the steam generator.

• 대한의용생체공학회:의공학회지
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• 제18권1호
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• pp.79-86
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• 1997

This paper describes the development of portable arousal measurement and analysis system. Skin impedance change which responds to the change of arousal level was detected by the three elctrode constant current method and separated into two components(SIR, SIL). Relationship between Nz, IRI and arousal level was studied and criteria of arousal level control was decided by the sleep study. Measured data with and without warning signal were compared and analyzed.

• 한국식품과학회지
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• 제32권6호
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• pp.1418-1425
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• 2000

아가리쿠스 버섯(동결 건조, 온풍 건조)에서 추출한 ${\beta}-glucan$을 7주령의 db/db마우스에 5주간 음용수로 제공하고 식이섭취량 및 체중의 변화를 관찰하고 혈액내의 포도당, 인슐린, 당화 헤모글로빈, 소장의 glycosidase의 활성을 측정하고 중성지방농도, 혈중 지질조성을 측정하였으며 결과는 다음과 같다. db/db 마우스에서 Agari.F군과 Agari.H군은 식이섭취량에서 Control군보다 유의적으로 낮았고, 그에 따라 체중증가량도 낮았으며, 혈중 인슐린 농도와 당화헤모글로빈 농도는 Control군에 비해 Agari.F군, Agari.H군, Acarbose군이 유의적으로 낮은 수준이었다. 소장의 maltase, lactase, sucrase의 활성은 Control군에서 Lean군에 비해 세 효소의 활성이 매우 높게 관찰되었고, 시료투여군인 Agari.F군, Agari.H군은 maltase의 경우 proximal, middle 부위는 대조군보다 낮았고 distal 부위에서는 Agari.F군의 활성이 가장 높았다. Sucrase, lactase의 활성은 모든 부위에서 시료투여군이 Control군보다 낮은 수준이었다. 혈중 중성지방 농도는 Control군에 비해 Agari.F군, Agari.H군, Acarbose군은 유의적으로 낮은 수준이었다. 혈중 total cholesterol의 농도의 경우 Control군과 Agari.H군은 유의적인 차이가 없었지만 Agari.F군과 Acarbose군은 유의적으로 낮았다. 혈중 VLDL cholesterol의 경우는 Control군에 비해 Agari.F군, Agari.H군은 유의적으로 낮았고 Acarbose군은 유의적인 차이가 없었다. 혈중 LDL cholesterol의 농도는 Control군이 유의적으로 높았으며, Acarbose군이 가장 낮았다. 혈중 HDL cholesterol의 농도는 Agari.H군이 유의적으로 가장 높았고, Control군이 가장 낮았다.

• 한국항공우주학회지
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• 제44권12호
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• pp.1035-1042
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• 2016

상용 비행시뮬레이션 게임 엔진 X-Plane을 이용하여 구성한 비행시뮬레이터에 대해 FTD level 5를 만족시킬 수 있는 QTG작성에 대해 연구하였다. 모델은 Cirrus사(社)의 SR-20을 대상으로 하였다. QTG의 테스트항목 중에는 조종반력을 측정하는 항목도 있다. 따라서 Brunner사(社)의 CLS(Control Loading System)을 조종 장치에 설치하여 조종반력을 측정할 수 있도록 구성하였다. X-Plane은 자체적으로 트림루틴을 제공하지 않으므로 외부에서 Autopilot을 구성하여 항공기가 트림상태에 도달할 수 있도록 하였다. 또한 테스트를 자동으로 수행할 수 있는 알고리듬을 개발하여 수동으로 조종하여 테스트하는 번거로움을 피하고 같은 테스트를 같은 조건으로 진행할 수 있도록 하였다. FTD Level 5의 경우 실제 비행데이터가 아닌 alternative data source를 적용할 수 있으며 이를 활용하여 모든 테스트 결과가 주어진 범위를 만족하였다.